1. Field of the Invention
The invention relates an audio-video output device and a car navigation system that can output video and audio information from a TV, a video player, or a car navigation system.
2. Description of the Related Art
Audio-video output devices, such as TV receivers, that can output images and voices are used in a wide variety of applications such as terminals for personal computers (PCs) and game computers. Furthermore, as flat and compact displays such as liquid crystal displays (LCDs) and plasma displays have become available in addition to the conventional CRTs, the applications for displays that can display video information are expanding further. Audio-video output devices equipped with a compact display such as an LCD are also being considered for embedding in cars. One of these applications is an on-board TV receiver which moves with the car and easily provides the enjoyment of TV programs in rest areas and camping sites. This receiver can also be used as the terminal of a car navigation system that indicates/displays the current position and the destination of the car to the driver using GPS (Global Positioning System) data. These audio-video output devices are also being used as the GUI (graphical user interface) terminals for controlling air conditioners and other systems.
As explained above, because audio-video output devices are equipped with the function of a terminal that provides information to users and into which information is input based on visual and audio senses, they are expected to be used in a wide variety of applications in the future, in addition to the applications described above. However, having multiple audio-video output devices for various different applications is inconvenient. For example, installing separate audio-video output devices for a TV, a car navigation system, and a video player in a small space inside a car would be a waste of space, and would also require multiple wiring and power supply facilities as well. Therefore, one idea being suggested is to provide an audio-video output device into which audio-video information for TV and audio-video information for car navigation can be input and displayed by switching the input sources, for example.
By configuring the device such that video information and audio information can be displayed by switching the input sources as explained above, a single audio-video output device can be used to output images and voices from multiple input sources. Therefore, a single audio-video output device can be used both as a TV receiver and a car navigation terminal in a car. However, since the input source must be switched for output, TV programs cannot be viewed when information such as destination and current location is being set using the device as the car navigation terminal. Conversely, even if a change occurs in the car navigation data, etc. while the device is being used as a TV, such a change cannot be communicated. As explained above, a device that displays information by switching the input source requires a small space and small hardware because a single display can display outputs from multiple input sources, and thus offers an advantage of lower overall system cost. However, such a device cannot display information from multiple input sources simultaneously. Therefore, in this respect, it would be more desirable to provide multiple audio-video output devices for the individual systems. However, providing multiple devices poses cost, hardware, and space issues as explained above.